


Thicker Water

by pprfaith



Series: Wishlist 2011 [11]
Category: Inception (2010), The Avengers (2012)
Genre: Alternate Universe, BAMF!Natasha, BAMF!arthur, BAMFness, Childhood, Family, Gen, Origins, Siblings, Slightly Unhinged Kids
Language: English
Status: Completed
Published: 2011-12-29
Updated: 2011-12-29
Packaged: 2017-10-28 10:57:42
Rating: General Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,034
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/307149
Author URL: https://archiveofourown.org/users/pprfaith/pseuds/pprfaith
Summary: <blockquote class="userstuff">
              <p>Arthur and Natasha rarely make it to their Gamma's birthday, but business keeps them in touch.</p>
            </blockquote>





	Thicker Water

**Author's Note:**

  * For [amusewithaview](https://archiveofourown.org/users/amusewithaview/gifts).



> **Prompt/Prompter:** Inception/Avengers, Natasha, Arthur, _Ruthless, dangerous, efficient: Natasha and Arthur rarely make it to their family reunions, but business keeps them in touch._ \- Amusewithaview
> 
> So, I speak four languages passably and know bits and pieces of about five more. That said, half of the foreign words used in this story come off google searches and I hope I didn’t screw up royally. Merry Christmas everyone and Merry Christmas Anna, I hope you like it because the prompt was a lot of fun and saving it for last was definitely the right idea.

+

Arthur has been at the orphanage for almost as long as he can remember. He was three when he came, Gamma, who isn’t really anyone’s grandmother, tells him. He remembers only flashes, bright, brief moments. Blood, noise, pain. They never tell him that his mother died, but he’s not a baby and he knows. He thinks he may have seen it.

But that’s all he remembers from before. He’s been here longer than any other child, almost five years. Matt used to be here longer, but he went away, so now it’s Arthur who knows the old, creaking house best of all. Not even the caretakers know all the nooks and crannies. They’re too big to fit.

+

Natasha comes from elsewhere, from outside. She’s a stranger in Arthur’s kingdom, so naturally he goes to inspect her as soon as Gamma leaves her alone. She looks around the yard for a while, inspecting the groups and clusters of children everywhere, and then finds the low wall surrounding the herb garden and sits primly on it. Her hair is redder than anything Arthur has ever seen, except maybe his mother’s blood when she screamed, but he doesn’t like to think of that.

He walks over to her, stops in front of her and says, “I’m Arthur. Who’re you?”

She looks at him for a long time and her eyes are very blue. Then she opens her mouth and says something in a language Arthur has never heard before. He frowns. This could pose a problem, he thinks, but then shrugs and pulls out a little leather ball filled with rice and holds it out to her.

By the end of the day, Natasha knows all the necessary words for playing ball, catch and hide and seek. She still counts in her own language – Russian – but they’re working on that.

The other kids make fun of her for her accent, her strange, rattling ‘R’s, but Arthur kind of likes them.

“Sister,” he says, carefully and slowly, pointing at her.

“Sis-terrrr,” she repeats, face blank and eyes sharp.

He shrugs. “Good enough.”

+

Natasha’s parents were immigrants from Russia, poor and careworn and they died in a fire. There was no-one to take her in, so she landed in the orphanage, with Gamma and the caretakers, Milly and Hetty and Annie, aging matrons all of them, but good to the children and always gentle with them.

Arthur finds her on her first day with the strange women in the strange old house. She doesn’t even know his name before she decides she likes him. He has dark hair and dark eyes and he looks _sharp_ , like the knives of the men that made her daddy so afraid and then set the house on fire when he didn’t want to play anymore.

She stares at him for a long time but he doesn’t get scared at all. She decides to keep him.

+

Neither of them is quite right in the head. It takes Arthur a while, but eventually he figures out that that’s why the other kids never do more than poke fun from a distance. They’re scared of him and Tasha.

“The two of you are fierce, my dear,” Gamma says when he asks about her. “You remind me of a story my grandmother used to tell me. Would you like to hear?”

She tells them about fey children, about changelings and even though she cuts the story down to size for a pair of ten-year-olds, Arthur reads between the lines, reads: beautiful and terrible.

“Why?” he asks afterward. Natasha stands half a step behind him, as always, silent and vigilant.

She sighs, strokes his cheek and smiles at Natasha. “Because you both saw bad things, my dear, and they changed you.”

“Can you fix it?”

She shakes her head, grey and bowed for as long as he can remember, “I’m sorry.”

Tasha smiles at her over his shoulder and says, “It’s okay.”

And it is.

+

At home, the other kids never make trouble because the ladies won’t allow it and Arthur and Natasha are just this weird constant in their lives. But at school it’s different. At school, people do bad things to them all the time.

Or try to, at least.

They lock Arthur in a storage closet, so he learns to pick locks.

They shove Tasha, so she learns to duck away and weave behind them, tripping them on the way.

They hit Arthur, so he learns to hit back, hard and fast and where no-one expects him to.

They hit Tasha, so she blackmails a boy into giving her his knife and learns to use it because she’s not strong but she’s _fast_.

They learn to run and hide and communicate silently, to evade and maneuver and be better than anyone else. They could just be quiet, could just avoid trouble, but it doesn’t even occur to them.

Anyone who comes to them wanting a fight _gets_ one and the teachers call them the Terrible Twins because they’re the smartest in their class and dangerous and vicious when cornered. They don’t mind because they always win.

+

“I am so bored,” Arthur says, throwing his small, worn leather ball at the wall and then drawing it back with the heel of his foot when it flops onto the floor like a dead fish. He’s speaking Russian because Tasha has been teaching him. It’s a recent thing that started when she realized she was forgetting the language. They’re already done with Spanish and French, each taking one language at school, teaching the other after hours.

“Everything bores you,” she informs him from where she’s sprawled on his bed, taking up too much space.

“Yes, well, everything _is_ boring.”

Silence. Then. “I want to go swimming.”

“It’s January.”

She calls him an impolite term she refuses to explain to him and then suggests, “The pool at school is heated.”

“Also: locked,” he tells her, playing the devil’s advocate.

“Thirty seconds,” she shoots back.

“Security fence.”

“Scale it.”

“Guard.”

“Seventeen minute rounds once every two hours.”

He sighs, pretending to be terribly put-upon, when he’s already fingering his homemade lock picks in his pocket. “Bet you I can do it in twenty,” he tells her.

He does it in sixteen.

+

When Arthur is almost seventeen and Natasha just turned sweet sixteen, a man comes to talk with Gamma. He says he’s a Russian government official. Tasha looks at him hard and cold and then tugs Arthur aside.

“He’s here for me,” she whispers in their very own potpourri of languages.

He frowns. “Why would he be?”

She shrugs and looks at her sneakers. “I remember his face from Russia. From when we got out.”

“I thought you said you got here legally.”

“We did.” She looks at him again, sky blue eyes, measuring him, like the first day, and finding something she understood. He found something in her, too. She watched her parents burn. He watched his mother bleed out.

It changed them. It taught them a lot of things about the nature of the world, and about people. One of them is this: Nothing comes for free.

The man introduces himself as Yuri and says he knew Natasha’s parents. He says he’d like to take her with him and it doesn’t sound like a suggestion. He says there is a government program. Tasha looks at Arthur, looks at the rickety, old house around them, the less traumatized, less alien children playing in the yard. They don’t pick locks, scale fences and learn security guard schedules by heart just to break into the school’s swimming pool. They don’t hide blades under their pillows and they don’t dream of fire and blood.

Arthur knows what she’ll say before she ever opens her mouth to speak.

“Bonne chance,” he whispers in her ear as they stand on the front porch, waiting for Yuri to pull the car around, not looking at each other, but clutching each others’ hands like they’re children again.

“Nyet,” she whispers back. “Not luck. Skill.”

He laughs and then recites the old game, the old word. “Syestra. Hermana. Soeur.”

“Sis-terrr,” she says, pronouncing the ‘R’ all wrong. “Brother.”

+

Arthur signs up for the army the very day he turns eighteen and as soon as he has his diploma in hand, he packs his bag, kisses Gamma goodbye and promises to be there for her birthday, the biggest of all holidays at the orphanage.

Then he sets out the way Natasha did before him, not knowing what’s coming, but knowing it’s going to keep him on his toes.

He flies through basic, draws the right kind of attention and then the wrong kind and then gets drafted for black-ops missions that sate the _hunger_ that’s been gnawing at him all his life.

He sends presents every year for Gamma’s birthday and Christmas, but he never goes home because he knows Tasha won’t be there.

+

The men in his unit nickname him King, because of King Arthur.

“King of what?” he asks one night, mostly drunk and still a little high from adrenaline, his favorite drug.

Johnson picks at the bandage around his arm with a grin. He would be dead if Arthur hadn’t shot him free, six bullets, six bodies and a nice fistful of C-4 to round it all of. No hesitation, no flinching. “How about Ice King? Since you piss ice cubes and all.”

Arthur flips him off, but the name sticks.

+

While Arthur carves a name for himself in the world of black-ops, Natasha trains in a remote Russian bunker, along with two dozen other orphans, children promised to the government, to the project, long before they were born.

Some of them wash out. Some of them run away. Some of them die. Out of all of them, Natasha is the only one there voluntarily.

Out of all of them, Natasha is the only one who speaks four languages and has an unhealthy fascination with fire.

The project is code named Black Widow, for reasons no-one in the new Russia quite remembers. Soon, it’s the name they call her when she passes them in the hallways. Mother Russia’s prodigy. Their new assassin.

+

The job is easy. Get in, kill the dozen or so men keeping an American dignitary hostage, get the hostage, get out.

They’re about to go in when one of the men notices a shadow moving on the roof. They all go down, guns at the ready, when the shadow becomes a shape with hair the color of blood. It’s a shade Arthur dreams about.

“Sister,” he says, relaxing his position despite his CO’s glare. Natasha won’t hurt him. He knows that much.

“Bruder,” she returns, lips quirking slightly.

“New language,” he commends.

“New life.” For both of them. It feels right, though. It feels like it always has. Her and him and sixteen seconds to crack that lock.

“Mission?”

She cocks an eyebrow at the men surrounding him, them shrugs. Trust. “There’s some files in that building. They need to disappear.”

He looks at his CO, who glares and pulls him back down. “What the fuck, King?” he asks sharply.

Arthur shrugs. “Meet my sister, sir. We’re not killing her.”

He doesn’t even pretend to make it sound like a request, which is probably a bad thing, but fact is, he’ll gun down his entire unit if he has to, for Natasha. So. His CO looks at Natasha, looks at Arthur. “You trust her?”

“With my life.”

“You only want the files?”

She nods.

“Okay.”

Arthur straightens with the rest of his unit and closes the gap between them. They don’t hug because they’ve never done that, but they look at each other long and hard and then they smile. He takes his hand off his gun, she takes hers off a hidden knife and they meet in the middle, squeezing.

“Hostage,” he says. “Second floor.”

“Rooftop access?”

“Electronic locks.”

“Ninety seconds.”

He grins, wide and open, like he did before he broke the nose and two fingers of a guy that looked at Natasha too long. Johnson quietly crosses himself. “Fifty,” Arthur retorts.

“Prove it.”

Apart from the men at their backs and the explosion Natasha makes bloom up behind them, it’s pretty much still like when they were kids.

+

“Do you go home for Gamma’s birthdays?” He asks later, before they split again.

She shakes her head. “Never.”

He didn’t expect her to.

“Do you write?”

“Da.” He accent is stronger than it once was. But their language, their own private tongue, still flows from her lips like she’s been speaking it all along.

“Me, too.”

The next time he receives a letter from Gamma and the ladies, there’s an extra sheet packed into the envelope, filled with Tasha’s tilted scrawl.

The next time Natasha finds the time to pick up her mail from a dummy address in her dead mother’s name, there’s a letter from Gamma with an extra sheet tucked inside, filled with Arthur’s neat copperplate.

+

Her hands don’t shake.

Natasha is twenty-two, standing over the man that calls himself Yuri and her hands don’t shake. Hands of a surgeon. Hands of a thief. Hands of an assassin.

“Why did you have my parents killed?” she asks and she speaks English because he hates it, because it’s the language of good things. And by good things she means Arthur. She barely remembers her parents but she remembers her brother and the trade is fair. She’s alright with it. Doesn’t mean she’ll let this slide.

Yuri spits a mouthful of blood and she kicks him in the side.

“They tried to hide you from us,” he laughs in Russian. “And then you came with me of your own free will. They would be so proud of you, Natashen’ka.”

“I’m killing you,” she answers. Doesn’t say _with what you taught me._

He hears anyway and laughs again, glint of pride in his eyes. It can’t be helped, though, so she just shoots him.

+

Arthur’s exit is less dramatic, but far more impressive, if he does say so himself. He walks out of a top secret government facility at the age of twenty-four, a million dollars in state-of-the-art equipment in his hands and no-one even tries to stop him.

He gets in his car, drives all night and then gets on a plane that takes him to Spain, where he sits down next to a man he knows only as Mr. Eames.

Eames slips his sunglasses up to his forehead, smirks and says, “Impressive, darling.”

They spend the next three days drunk on champagne and victory, until a shadow falls over them and Eames gives a low whistle.

“Freelancing?” the shadow asks and Arthur squints up at Natasha and shrugs.

“I got bored again.”

“Arthur, darling,” Eames drawls, only half coherent. “Introduce me to your girlfriend.”

“Sister,” Arthur corrects, voice a bit sharp. “Hands off.”

“Will you hurt me if I don’t?”

“I will,” Tasha says blankly and kicks Arthur’s feet off his lounge chair to sit down.

+

They get drunk together, laughing about old childhood stories, entertaining Eames endlessly.

The next morning Arthur wakes to an indent in the second pillow on his bed and no Natasha. Eames, who slept on the sofa, presents him with a heavy sheet of textured paper over hang-over breakfast. There’s a sketch on it, quick, bold lines of Arthur and Natasha sleeping on their sides, facing each other. It’s black and white, the differences in their coloring erased, leaving only structure. High cheekbones, sharp chin, slanted ears, half hidden under loose hair.

They look like actual siblings.

Sister. Syestra. Soeur. Hermana. Schwester. He knows the word in nine languages by then. He forgot to ask her how many she has.

+

“Everything my contacts knew and everything I could dig up,” he says as he slips her a USB drive on a bench in a public park in London, two minutes’ walk from the British Museum.

She smiles her thanks at him quickly and then goes back to watching the children playing in the central fountain, screeching as they sprint through the water, arms spread wide.

“Are you going to accept?” He already knows the answer.

SHIELD is big and it’s dangerous and has more secrets than a year has days. It’s perfect for his little sister, who likes life the same way he does: fast, hot and deadly.

“Yes.”

+

The first time he works with Cobb, they get into one hell of a jam on the second level and Arthur’s projections go a bit crazy. Then, suddenly and out of nowhere, a redheaded woman in a skintight jumpsuit shows up, armed to the teeth, expression cool and controlled as she pulls them into a dark alleyway and says, “Shortcut, follow me.”

“Who’s she?” Dom asks as they follow her at a dead run through twists and turns they never would have found on their own, even through Dom built this maze and Arthur is dreaming it.

“Security,” Arthur returns as he manifests a gun and shoots a projection about to attack the redhead. She doesn’t even flinch, just ducks, spins, and sends a knife flying over his shoulder, killing another one.

+

Cobb meets the redhead in real time when he wakes from a botched job to the sound of gunshots. He rolls under his lounge chair, pulls his gun and hears Arthur shout something in no language he has ever heard before.

More gunshots.

Eames appears out of nowhere and pulls Dom to his feet, grinning big enough to split his face. “Gorgeous aren’t they? Death times two.”

He points toward the other end of the warehouse, where Arthur is crouching back to back with the woman from his dreams, racking up a body count.

Moments later the men that attacked them are dead on the floor and the woman stands, brushes her hair out of her face and moves toward their mark, still heavily sedated.

“Hey!” Dom tries.

She shoots him a look, then turns to Arthur. “You were trying to extract from my mark.”

“You were trying to kidnap my mark,” he shoots back.

“I saved your life.”

“I saved yours.”

For a minute, they glare at each other fiercely. Then Arthur shrugs. “You take him, you go to Gamma’s birthday this year,” he demands.

She pouts, then sighs and says, “Get out then.”

They do. Eames blows her a kiss on the way. Arthur punches him in the arm hard enough to make him wince.

+

“So,” she drawls as she sinks into the booth right next to him, touching him from knee to neck. “Inception?”

He finishes his drink before turning to smile at her. “How do you know this?”

She shrugs and reaches for his empty glass, shaking it to make the leftover ice clink against the sides. “I have my sources.”

Meaning SHIELD. Which is interesting because Arthur didn’t think SHIELD has any interest in dream sharing. It’s not the kind of threat they usually deal with.

“I thought information was my business?”

She spreads the fingers of her free hand on the table, wide and open. “I’m branching out.”

Arthur raises his hand, two fingers extended. The waitress nods and brings two new glasses of scotch. He tips his toward Natasha, toasts, “To your career, then, soro.”

“To your retirement,” she returns and then smirks as she adds, “frate.”

+

“Is that…?” Dom asks, scooting forward on the sofa and pushing his daughter’s arm out of the way to point at the TV, where a redheaded woman in a jumpsuit is doing acrobatics around a horde of giant, mutant spiders.

“Is that who?” Ariadne demands from the armchair where she’s doodling on a sketchpad.

“No,” Arthur cuts in before Dom can finish, his look forbidding. “Don’t say it.”

Dom frowns, but seeing the threat in Arthur’s eyes, relents and nods. “Former client,” he offers. Ariadne doesn’t buy it but she knows how to leave well enough alone.

There are maybe a dozen people in the world that know that Arthur and Natasha are siblings. But there is only one person left alive in the world that knows that the Pointman and the Black Widow, too, are siblings. And Eames would die before he tells.

Arthur intends to keep it that way.

+

It doesn’t work because these things never work and one morning, a year into being an Avenger, Natasha gets an unmarked envelope in the mail. It contains a DVD. She pops it into the player and watches, still as a statue, as men in black masks beat a man suspended by his wrist into a bloody pulp.

His breathing is flat, like there are ribs already broken and his eyes are swollen shut and his jaw is clenched so tightly she knows he’s grinding his teeth.

“Who is that?” Steve asks, his voice low, worried, angry.

Natasha’s hands go to her knives and then settle on her phone instead of answering. “Mr. Eames,” she says as soon as he picks up.

“Darling. How’d you get this number?”

“When have you last seen Arthur?”

Tony mutters something under his breath and JARVIS hijacks her phone with a low whirring noise and then everyone in the room can hear. She glares at Tony. “Three days ago. He’s on a job. Would you like me to hustle him up for you, darling?”

“He’s been kidnapped,” she tells him.

Silence. Then, “I’m taking it this isn’t the usual rush-job that he kills his way out of in time for dinner?”

Eyebrows go up around the room and Clint smirks in dark appreciation. Natasha doesn’t answer, which is answer enough. Eames grunts into the phone. “I’ll go talk to a few blokes.”

He hangs up without goodbye and Steve repeats his question, gentler and, perhaps, angrier. “Who is that man?”

“Frate,” Natasha answers, “Bruder. Hermano. Bratyshka” She has seventeen languages to say brother in and somewhere, someone, is beating him to death to get to her. “He is my brother.”

Steve nods and everyone scurries to get to work.

+

It takes them fifteen hours to find out where he is and get there and by the time they do, Arthur is hanging in his chains like a ragdoll. A broken ragdoll.

All around them the fight is still going strong as Natasha leans into him and motions for Iron Man to help cut him down. Arthur leans his forehead against her shoulder, smearing blood. “Did you stop for coffee on the way?” he asks, low and secret, in their very own language.

Iron Man, who possibly speaks as many languages as Natasha does and understands Arthur, barks a tinny laugh and finally manages to unlock the chains.

“Syestra,” Arthur breathes into her neck.

“Brother,” she returns. Behind her, a door swings open and she knows that she won’t be fast enough. Arthur’s hand slides down her back, grips the gun there and rises again. He shoots blindly, three times, hitting the man in the chest every time.

Then he straightens, sways, stays on his feet.

“Let’s get out of here,” Iron Man chirps, inspecting the body. He tries not to sound impressed and fails, adds, “I guess that runs in the family, huh?”

Natasha draws her other gun back out, passes one of her knives to her brother, then grips its twin in her own free hand.

“Two minutes to the exit,” she says, giving him a brief grin.

“Ninety seconds,” Arthur argues as he hefts the knife and smirks, distorted through dried blood and swelling bruises.

It only takes them eighty two.

+

“I think,” Arthur informs the room at large, sounding somewhat dazed, “Fury just offered me a job.”

“Criminal record?” Natasha asks, making the other Avengers look up in interest.

Arthur shrugs. “I’ve been officially dead since oh-four. What’s to record?”

“Will you accept?”

“Are you going home for Gamma’s birthday next week?” he asks, and that’s as good an answer as any.

Tony mumbles something about freaky ninja thighs of death times two and ogles Arthur and Natasha both. So predictable. She ignores her teammate, focuses on her brother and nods. “Probably.”

He shrugs, nods. “Good enough.”

+

“Still bored?”

“No.”

+

**Author's Note:**

> [My tumblr](https://www.tumblr.com/blog/wordsformurder) is now open for fandom business. Come visit.


End file.
